#define _CRT_SECURE_NO_WARNINGS 1
int missingNumber(int* nums, int numsSize) {
    int sum1 = 0;
    int sum = numsSize + (numsSize * (numsSize - 1)) / 2;
    for (int i = 0; i < numsSize; i++)
    {
        sum1 += nums[i];
    }
    return sum - sum1;
}